A golf club consists of a club head, a shaft extending out of the club head, and a grip or handle that is held by a player while swinging the golf club. There are numerous parameters in the design of a golf club that affect how far a golf ball can be hit with the club. Some of these include the weight of the club head, the loft angle of the club head, the face angle of the club head, the lie angle of the shaft, the position of the center of gravity within the club head, the spring effect of the club head, the length of the shaft, and many others.
Selecting parameter values for a golf club is usually done in a coordinate frame of reference known as a design reference frame, also called design frame. This frame of reference provides a set of orthogonal axes in which the size, position and angle of various structural elements of the club are defined by a designer. The design reference frame is defined relative to structural elements of the golf club and without reference to the swinging of the golf club such that the orientation of the golf club is static relative to the design frame, even while the golf club is being swung.
One problem with designing club heads within the design frame is that changes in the orientation of the club head caused by swinging the club are not reflected in the design frame. In particular, as the player grips and swings the club, the club head's orientation is rotated along each of three orthogonal axes. However, since the design frame is “anchored” to the golf club head, these changes in orientation will not be reflected in the coordinates of the design frame. For example, the position of the center of gravity and the position of the center of the club face are constant in the design frame even as the club moves during the swing. As a result, it is not possible to model the relative position and orientation of elements of the club head in relation to the golf swing using only the design frame.
The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter.